Maxon Valv
es
alves
Page 6105
Design Features and Operating Concepts
Valv
es with electro-mechanical actuators
alves
for quick opening or closing action
Normally closed shut-off valves are used in
burner system fuel supply lines on industrial boilers,
furnaces, ovens, kilns, and other heating processes.
All valves are designed to shut-off fuel automatically
and instantly with any interruption in the electric
power supplied through your safety circuit.
Normally open vent valves are most often used
as the bleed valve in a block-and-bleed pipe train,
sometimes required by insurance authorities. They
are designed to open a vent line automatically and
instantly upon any interruption in the electric power
supply through your safety control circuit.
These valves are also used for the manual or
motorized opening or closing of pipe lines carrying
gases and liquids commonly used in industrial processes. Normally closed valves cannot be opened until
the interlocking safety control circuit is proven and
resulting electrical power is supplied to the shut-off
valve.
These normally open valves are also used in
protective atmosphere systems and other gaseous
and fluid service requiring quick opening or by-pass
purging action.
Motorized automatic valve actuators are used
where remote access or unmanned applications are
needed.
NOTE: Valve motors are protected against thermal
overload. Normal duty cycles of 1 cycle per minute or
less should allow motor thermal overload to sufficiently cool between cycles. If the normal valve duty
cycle is exceeded, the motor must be allowed to cool
before the thermal protection will automatically reset.
Manual reset actuators require operating personnel to be physically present to actuate the valve from
its at rest position.
1/99
Like the normally closed versions, both automatic
and manual reset actuators are available for remote
access locations, or when operating personnel's
physical presence is preferred.
All Maxon valves feature one-piece cast iron or
cast steel bodies with micro-lapped seats and discs.
Straight through flow path minimizes pressure drop
through full open swinging gate or rising stem (guillotine action) bodies.
Page 6106
Maxon Valv
es
alves
Valv
e Body Design Details
alve
To provide seals in your process service lines, Maxon uses
two different styles of valve bodies:
Valve Body
Assembly
Seat
Rising stem (guillotine action) bodies are frequently used
in normally closed and normally open gas valves. The microlapped, spring loaded guillotine disc gets a pressure assist from
the flowing gases to seal against the downstream micro-lapped
metal seat ring. The carefully machined seal surfaces and
extremely close tolerances of the valve body operating mechanism promote positive closing action. Frequent cycling action
constantly shears accumulated dirt or residue from the disc and
seat to insure instantaneous and reliable sealing.
The location of the port in the disc is the basic difference
between normally open and normally closed valve bodies. Both
valves function by the top assembly mechanism driving the stem
and disc down into the valve body, opening (or closing) the flow
path. Both valves trip to their rest position when their top
assembly's compression spring is released to pull the stem and
connected disc up out of the body.
Normally-Closed
Disc
Normally-Open
Disc
Valve Body
Assembly
Disc
Carrier
Swinging gate bodies are frequently used in normally closed
oil valves and for some non-combustible gas applications. This
design provides the same seal capabilities, but in a slightly
different operating mode. The hard faced micro-lapped seat nut
is threaded into the one-piece valve body. The free-floating, hard
faced, spring loaded circular disc swings across the seat. Line
pressure also assists in sealing the disc to the downstream seat.
Here again, frequent use and cycling actually helps to keep
your valve clean. Since the free-floating disc is swinging across
the circular seat nut on the arc created by the disc carrier, the
disc rotates slightly on every cycle. This provides a fresh, clean
surface area for sealing off the flow lines.
Disc
Seat
Maxon valve bodies have special service trim options
available to meet your particular fluid service requirements.
Contact your Maxon representative for details.
Maxon Valv
es
alves
Page 6107
Valv
e Body Capacities/Specifications
alve
Table 1: Normally closed valve bodies
Body
End
Pipe Size
Material Connections (in inches)
.375 & .5
.75
1
Threaded
Gray
Iron
1.25
3.4
SG
Body
Type [1]
.75
20
RS
1
20
RS
1.5
53
RS
9.6
SG
20
RS
12
SG
2
86
RS
20
RS
2.5
304
RS
17
SG
3
423
RS
Threaded
Gray
Iron
RS
2
86
RS
RS
2.5
304
RS
2
86
RS
3
423
RS
127
RS
4
490
RS
304
RS
173
RS
423
RS
86
RS
127
RS
2.5
3
4
6
RS
2
86
RS
2.5
304
RS
3
423
RS
490
RS
490
RS
719
RS
869
RS
Each complete valve assembly must include one of
these valve bodies, regardless of ultimate series
designation.
Flows through the valve body and resulting pressure drops may be estimated by inserting your
specific conditions into the following formula and
using Cv flow factors given for each valve body.
.75
9.6
SG
12
SG
20
RS
17
SG
45
SG
53
RS
Stainless
2
86
RS
Steel
2.5
304
RS
3
423
RS
490
RS
719
RS
869
RS
1172
RS
6
RS
53
4
RS
4
Flanged
20
RS
SG
1.5
Cast
Steel
1
1.5
423
3.4
1.25
Threaded
RS
1172
Threaded
Flanged
304
.5
1
[1] RS = Rising Stem valve body
SG = Swinging Gate valve body
See catalog pages 6117-6119 for construction details.
NOTE: Typically, pressure drop for gas flows should not
exceed 10% of inlet pressure; however, for 2" and smaller
valves, the drop should not exceed 5 PSIG, and for 2.5" and
larger valves, must not exceed 2.5 PSIG.
Select valve size on basis of the lower of these parameters
to avoid critical flow conditions.
2/00
Cv
Factor
45
2
Flanged
Body
End
Pipe Size
Material Connections (in inches)
53
3
Cast
Steel
or
Body
Type [1]
1.5
2.5
Flanged
Cv
Factor
Table 2: Normally open valve bodies
Gases: Q = (1360) x (Cv) x
(P1+P2)
G Tf
Liquids: V = (Cv) x
x
(P1–P2)
2
(P1–P2)
Gf
Where:
G =
Gf =
P1 =
P2 =
Q =
Tf =
V =
Gas specific gravity (air = 1.0)
Specific gravity @ flowing temperature °F
Inlet pressure PSIA (14.7 psi + psi gauge)
Outlet pressure PSIA (14.7 psi + psi gauge)
Cubic feet per hour @ 14.7 PSIA and 60°F
Flowing temperature absolute (460° + °F)
Flow in U.S. gallons/minute of water
Page 6108
Maxon Valv
es
alves
Valv
e Body Capacities
alve
al Gas at 5 inches w
.c. Inlet Pressure
Natural
w.c.
with Natur
Approximate pressure drops
for various valve sizes and flows
C v may be determined by using this
1172
C v graph.
869
Typically, pressure drop for
Cv
719
fuel flows should not exceed
C v 10% of inlet pressure.
490 v
Select valve size on basis of
C
423
the lower of these parameters
C v to avoid critical flow conditions.
304
50000
C
6" H
S
6" R
C
4" H
P RS
4" C P RS
3" C
S
CP R
2.5"
5000
173
Cv
127
S
3" R
RS
2.5"
v
86 C
S
2" R
v
53 C
v
C
45
RS
1.5" RS
"
1.25
v
20 C
S
1" R
&
"
.75
500
0.2
Cv
0.3
0.4
0.5
Maxon Valv
es
alves
Page 6109
Valv
e Body Capacities
alve
with Natural Gas at 1 PSIG Inlet Pressure
Approximate pressure
drops for various valve
sizes and flows may be
determined by using this
graph.
Typically, pressure drop
for fuel flows should not
exceed 10% of inlet
pressure.
Select valve size on
basis of the lower of these
parameters to avoid critical
flow conditions.
500000
v
2C
117 v
C
869 Cv
719
Cv
490 Cv
423 v
C
3 04
HC
6" S
R
6 "" HC
4
S
PR
C
4"
S
PR
C
3" P RS
"C
2.5
RS
3"
S
"R
2.5
RS
2" S
"R
1.5
S
5" R
2
.
1
RS
1"
&
"
.75
50000
5000
Cv
173 v
C
127
Cv
86
Cv
53 v
C
45
Cv
20
500
0.5
1/99
5
Page 6110
Maxon Valv
es
alves
Valv
e Body Capacities
alve
with Natural Gas at 5 PSIG Inlet Pressure
v
2C
7
11 v
9C
86 9 Cv
71 v
0C
493 Cv
42 v
4C
30
v
3C
17 v
7C
12
Cv
86
Cv
53 Cv
45
500000
HC
"
6 S
R
6"" HC
4
RSS
P
R
C
S
4"3" C P P R
"C
2. 5
RS S
"
3 R
5"
2. S
R
2"
RS
"
5
S
1.
"R
5
1.2
RS
1"
"&
.75
50000
5000
Cv
20
500
0.5
5
50
Approximate pressure drops
for various valve sizes and flows
may be determined by using this
graph.
Typically, pressure drop for
fuel flows should not exceed
10% of inlet pressure; however,
for 2" and smaller valves, the
drop should not exceed 5 PSIG,
and for 2-1/2" and larger size
valves, must not exceed 2.5
PSIG.
Select valve size on basis of
the lower of these parameters to
avoid critical flow conditions.
Maxon Valv
es
alves
Page 6111
Valv
e Body Capacities
alve
with #2 Oil
To select a valve for
YOUR application, use
either Cv factor calculations, or this graph
showing approximate
pressure drop at various
flows of #2 oil.
Typically, pressure
drop for fuel flows
should not exceed 10%
of inlet pressure.
For preheated #5 or #6 oil, multiply
the required flow rate in GPH by the
factor given in the table at right, then
select a valve based upon that equivalent flow of #2 oil and the allowable
drop.
1/99
Oil Grade
#5
#6
°F @ Inlet
125
160
120
140
180
210
220
Factor
1.43
1.11
2.86
2.00
1.25
1.11
1.05
For example: To size for 5 PSIG drop with a 3500 GPH flow of #6
oil preheated to 140°F, the multiplier is 2. Equivalent flow of #2 oil
is then 3500 x 2, or 7000 GPH. Chart shows that a 5 PSIG drop will
require use of a valve body having a Cv factor of at least 45.
Page 6112
Maxon Valv
es
alves
Selection Data
Normally closed, swinging gate valves
Features:
Series Designation
Body Material>
Top Assembly
Function
Gray Iron
Sanctioned
Service [1]
Cast Steel
Special Service
(Non-sanctioned) [2]
• Normally closed
Sanctioned
Service [1]
Special Service
(Non-sanctioned) [2]
• Electrically actuated
• Swinging gate body
• For shut-off service
Manual Reset
730
790
730-S; 760
790-S
33790; 23300
Automatic Reset
4730; 8730
4790; 8790
4730-S
4760; 8760
4790-S; 8790-S
33479; 25300
[1] Sanctioned valves are sold for fuel oils and may carry one or more sanctions (UL, FM,
CGA). They are IRI approvable for liquified petroleum gases, #1 and #2 fuel oils, kerosene, JP4 and preheated #4, #5 and #6 oils with maximum viscosity of 5000 SSU.
[2] Non-sanctioned valves do not carry blanket approval/listings, and the pressure limits shown
apply only for selected special service applications. An analysis of your fluid will determine the
actual rating, trim, and specifics for your application.
• For liquid and noncombustible gas service
Temperature Limits
All of these valves can handle fluid temperatures from -20°F (-28°C) to
+250°F (+121°C). The Series 33000 valves are designed to handle higher
fluid temperatures up to +450°F (+232°C) and even up to +550°F (+288°C)
with addition (at extra charge) of special stem seals.
Ambient temperature limits vary. Any valve on this page using DC
voltage and all Series 8700 valves can handle ambient temperatures from 20°F (-28°C) to +125°F (+52°C). The other valves on this page handle
ambient temperatures from -20°F (-28°C) to +140°F (+60°C).
Operation
All of these electro-mechanical valves require a constant supply of
electrical energy to their holding solenoids inside the top assembly actuators. Once the solenoid is energized, the manual reset valve may be opened
manually, or the automatic reset valve will automatically open. Any interruption of the electrical power to either of these valves causes an immediate trip
of the valve to its normally closed position.
1" Series 760
Available Sizes and Pressure Ratings
Pipe Size
(inches)
Body CV
Flow Factor
.375 [1]
3.4
.5 [1]
.75 [1]
9.6
1
12
1.25
17
1.25 HC
45
1.5
123
2
218
[1] Available in 8730, 8760 & 8790
Maximum Inlet Pressure (PSIG)
Gray Iron Bodies
Fuel Oils
Special Service
300
300
-------
-------
Shaded areas indicate 300# raised face flanged bodies.
Cast Steel Bodies
Fuel Oils
Special Service
-----
600
600
300
150
100
300
150
100
Maxon Valv
es
alves
Page 6113
Selection Data
Normally closed, rising stem valves
Features:
Series Designation
Body Material>
Gray Iron
• Normally closed
Cast Steel
Top Assembly
Function
Sanctioned
Ser vice [1]
Special Ser vice
(Non-sanctioned) [2]
Sanctioned
Ser vice [1]
Special Ser vice
(Non-sanctioned) [2]
Manual Reset
808; 808-CP
818; 818-CP
808-S; 808-S-CP
818-S; 818-S-CP
Automatic
Reset
5000; 5000-CP
7000
5100; 5100-CP
7100
5000-S; 5000-S-CP
7000-S
5100-S; 5100-S-CP
7100-S
• Electrically actuated
• Rising stem body
• For shut-off service
[1] Sanctioned valves may carr y one or more sanctions (UL, FM, CGA) for air, natural and liquified
petroleum gases. They are normally approvable for clean fuel gases. Additionally, series with internal trim
-2 are sanctioned for #1 and #2 fuel oils (except Series 7000 (-S) are not listed FM approved for #2 fuel
oil). 'SG' valves are preferable for liquid ser vice (see page 6112).
[2] Non-sanctioned valves do not carr y blanket sanctions, and the pressure limits shown apply only for
selected special ser vice applications. An analysis of your fluid will determine the actual rating, trim and
specifics for your application.
Temperature Limits
All these valves can handle fluid temperatures from -20°F (-28°C) to +140°F
(+60°C). Oil viscosity not to exceed 5000 SSU. Ambient temperature limits vary. Any
valve on this page using DC voltage and all Series 7000 valves can handle ambient
temperatures from -20°F (-28°C) to +125°F (+52°C). The other valves on this page
handle ambient temperatures from -20°F (-28°C) to +140°F (+60°C).
Operation
All of these electro-mechanical valves require a constant supply of electrical energy to
their holding device inside the top assembly actuators. (In Series 808 and 5000 valves,
the device is a solenoid and Series 7000 valves use an electro-magnetic clutch.) Once
that device is energized, the manual reset valve may be manually opened, or the
automatic reset valve will automatically open. Any interruption of the electrical power to
either of these valves causes an immediate trip of the valve to its normally closed
position.
4" Series 7000
Available Sizes and Pressure Ratings
Pipe Size
(inches)
Body CV
Flow Factor
.75
1
20
1.25
1.5
45
53
2
86
2.5
127
2.5 CP
304
3
173
3 CP
423
4 CP
4 HC [4]
6
6 HC [4]
490
719
869
1172
Maximum Inlet Pressure (psi) [3]
Gray Iron Bodies
Clean Gases
Special Service
Cast Steel Bodies
Clean Gases
Special Service
125
125
30
30
--125
--30
100
70
70
30
20
15
--70
70
--20
15
70
40
40
50
15
10
10
15
70
-- --50
15
----15
50
30
40
40
40
60
30
50
15
5
10
10
10
10
5
10
50
--40
40
40
60
30
50
15
--10
10
10
10
5
10
[3] Maximum operating pressure differential (MOPD) in psi must not exceed maximum inlet pressure shown.
[4] Series 7000 valves
NOTE: Shaded areas indicate flanged valve bodies. All others are threaded.
11/03
Page 6114
Maxon Valv
es
alves
Selection Data
Normally open, rising stem valves
Features:
Series Designation
Body Material>
Top Assembly
Function
Manual Reset
Gray Iron
• Normally open
Cast Steel
Sanctioned
Special Service
Sanctioned
Special Service
Service [1] (Non-sanctioned) [2] Service [1] (Non-sanctioned) [2]
STO-M
STO-M
STO-MS
STO-MS
Automatic
STO-A
STO-A
STO-AS
STO-AS
Reset
STO-A-CP
STO-A-CP
STO-AS-CP
STO-AS-CP
[1] Sanctioned valves may carry one or more sanctions (UL, FM, CGA) for air, natural
or liquified petroleum gases. They are normally approvable for clean fuel gases.
Additionally, series with internal trim -2 are sanctioned for #1 and #2 fuel oils.
[2] Non-sanctioned valves do not carry blanket sanctions, and the pressure limits
shown apply only for selected special service applications. An analysis of your fluid will
determine the actual rating, trim and specifics for your application.
• Electrically actuated
• Rising stem body
• For vent and by-pass
service
Temperature Limits
All these valves can handle fluid temperatures from -20°F (-28°C) to
+140°F (+60°C). Oil viscosity not to exceed 5000 SSU.
Ambient temperature limits vary. Any valve on this page using DC
voltage can handle ambient temperatures from -20°F (-28°C) to +125°F
(+52°C). The other valves on this page can handle ambient temperatures
from -20°F (-28°C) to +140°F (+60°C).
Operation
All of these electro-mechanical valves require a constant supply of
electrical energy to their holding solenoids inside the top assembly actuators.
Once the solenoid is energized, the manual reset valve may be manually
closed, or the automatic reset valve will automatically close.
Any interruption of the electrical power to either of these valves causes an
immediate trip of the valve to its normally open position.
2.5" Series STO-ACP
Available Sizes and Pressure Ratings
Maximum Inlet Pressure (psi) [3]
Pipe Size
(inches)
.75
1
Body CV
Flow Factor
20
1.5
53
2
86
2.5 CP
304
3 CP
423
4 CP
490
Gray Iron Bodies
Cast Steel Bodies
Clean Gases
Special Service
Clean Gases
Special Service
125
30
---
---
125
30
125 [4]
30
70
20
70
20
70
15
70 [4]
15
70
15
70
15
50
15
50
15
50
15
50
15
40
10
40
10
40
10
40
10
40
10
40
10
[3] Maximum operating pressure differential (MOPD) in psi must not exceed maximum inlet pressures shown.
NOTE: Shaded areas indicate flanged valve bodies. All others are threaded.
Maxon Valv
es
alves
Page 6115
Rising Stem Body/T
Body/Trr im Specifications
All Maxon Rising Stem Gate Valves carry a twopart trim identification (for example, Trim 1-1).
The first digit (a 1, 2, 3, 4 or 5 before the
hyphen) identifies valve body and bonnet
material as shown in Table 1 below.
The second digit (a 1, 2 or 3 after the hyphen)
identifies the specific internals used, as
described in Tables 2, 3 and 4, and identified in
the sketches at right.
Internal trim -1 is normally suitable for clean
fuel gases (for example, natural gas, propane,
butane, clean atmosphere gases).
Internal trim -2 may be required for clean
gases that require Viton seals or such gases as
coke oven, refinery, town or off-gas.
Internal trim -3 is designed for more corrosive
environments such as digester gas, sour natural
gas and landfill gas. Contact Maxon with specific
fuel analysis for prices and/or availability.
Normally closed and normally open threaded
and flanged body versions are identical in
material specifications.
The drawing at right carries item numbers
matching those in Tables 2, 3 and 4. This information is furnished for identification only, not for
ordering parts.
WARNING: Do not attempt field repair of Maxon valve
body or electro-mechanical actuator. Any field
alterations void all warranties.
Table 1: Body (Item 1) and Bonnet (Item 2) Specifications
Body Description
Material
Specifications
Special Coating
Body 1–
Body 2–
Body 3–
Cast Iron, G3000, CL 30
Cast Steel
ASTM A159 / UL 429
ASTM A216-WCB / UL 429
---- -
Body 4–
Body 5 –
Cast Iron, G3000, CL 30
Cast Steel
ASTM A159 / UL 429
ASTM A216-WCB / UL 429
Electroless Nickel-Coated Electroless Nickel-Coated
Stainless Steel
A351-CF8M
---
Table 2: Internal Trim Specifications
Item
No.
Trim: –1
Description
.75" – 2"
2.5", 3"
2.5" – 4" CP
6"
3
Seat
#440-F Stainless Steel
#416 Stainless Steel
#440-F Stainless Steel
#303 Stainless Steel
4
Disc
80-55-06 Ductile Iron
80-55-06 Ductile Iron
80-55-06 Ductile Iron
80-55-06 Ductile Iron
5
Follow Ring
Low-Carbon Steel
(nickel plated)
Low-Carbon Steel
(nickel plated)
6
Seat O-Ring
Buna N
Buna N
Buna N
Buna N
7
Gasket
Buna N
Buna N
Buna N
Steel
#302 Stainless Steel
#302 Stainless Steel
Leadaloy (nickel plated) Ductile Iron (nickel plated)
8
Wavy-Spring Washer
9
Stem
Type 630 Stainless Steel Type 630 Stainless Steel
#302 Stainless Steel
#302 Stainless Steel [1]
Type 630 Stainless Steel
Type 630 Stainless Steel
10 Stem/Disc Pins
High Carbon Steel
(hardened)
High Carbon Steel
(hardened)
---
Shear-Proof Steel
11 Stem O-Rings
Buna N
Buna N
Buna N
Buna N
#17-7 Stainless Steel
#17-7 Stainless Steel
#17-7 Stainless Steel
Carbon Steel (6" 808 only)
Buna N
Buna N
Buna N
Buna N
---
---
---
Ductile Iron
12 Striker Plate
13 Bumper
---
Clevis [2]
[1] Compression Spring
11/03
[2] For 6" 808 and 4" & 6" 7000 valves only; not shown in illustration above
Page 6116
Maxon Valv
es
alves
Rising Stem Body/T
Body/Trr im Specifications
Table 3: Internal Trim Specifications for Trim -2
Trim: -2
Item
No.
Description
.75" – 2"
2.5" – 4" CP
6"
3
Seat
#303 SS (hard faced)
#303 SS (hard faced)
#303 SS (hard faced)
4
Disc
80-55-06 Ductile Iron
(chrome plated)
80-55-06 Ductile Iron
(chrome plated)
80-55-06 Ductile Iron
(chrome plated)
5
Follow Ring
303 SS
(chrome plated)
303 SS
(chrome plated)
303 SS (chrome plated)
6
Seat O-ring
Viton
Viton
Viton
7
Bonnet O-ring
Viton
Viton
Steel
8
Wavy-Spring Washer
#302 Stainless Steel
#302 Stainless Steel
#302 Stainless Steel
9
Stem
Type 630 Stainless Steel
Type 630 Stainless Steel
Type 630 Stainless Steel
10
Stem/Disc Pins
#420 Stainless Steel
---
Shear-Proof Steel
11
Stem O-rings
Viton
Viton
Viton
12
Striker Plate
#17-7 Stainless Steel
#17-7 Stainless Steel
Carbon Steel
13
Bumper
Viton
Buna N*
Viton
*For oxygen service, bumper material is EPDM
Table 4: Internal Trim Specifications for Trim -3
Item
No.
Description
Trim: -3
.75" – 2"
2.5" – 4" CP
6"
3
Seat
PEEK
PEEK
PEE K
4
Disc
A351-CF8M
A351-CF8M
A351-CF8M
5
Follow Ring
PEEK
PEEK
PEE K
6
Seat O-ring
Viton
Viton
Viton
7
Bonnet O-ring
Viton
Viton
Viton
8
Wavy-Spring Washer
#302 Stainless Steel
#302 Stainless Steel
#302 Stainless Steel
9
Stem
Type 630
Stainless Steel
Type 630
Stainless Steel
Type 630
Stainless Steel
10
Stem/Disc Pins
---
---
---
11
Stem O-rings
Viton
Viton
Viton
12
Striker Plate
#17-7 Stainless Steel
#17-7 Stainless Steel
#17-7 Stainless Steel
13
Bumper
Viton
Buna N*
Viton
*For oxygen service, bumper material is EPDM
Maxon Valv
es
alves
Page 6117
Swinging Gate Body/T
Body/Trr im Specifications
Trim identification of Maxon Swinging Gate ShutOff Valves is two-part. The first digit before the
hyphen is a number (1, 2, 3 or 4) identifying body
material as shown in Table 1 below. The second digit
after the hyphen identifies a trim utilizing the materials
indicated in Table 2 below.
Standard sanctioned valves incorporating a cast
iron body will normally be identified by trim 1-B or
1-D. Sanctioned valves with steel body will normally
be trim 2-D.
Non-sanctioned services or unusual applications
may require upgrading of internal trim. Contact Maxon
with specific fuel analysis for price and availability.
The drawings shown on the following page carry
item numbers matching those in Table 2. This information is furnished for identification only, not for
ordering parts.
WARNING: Do not attempt field repair of Maxon valve
body or electro-mechanical top actuator. Any field
alterations void all warranties.
Table 1: Body (Item 1) Specifications
Body Description
Body 1-
Body 2-
Body 3-
Body 4-
Material
Cast Iron, G3000, CL 30
Cast Steel
Cast Iron, G3000, CL 30
Cast Steel
ASTM Spec
A159
A216-WCB
A159
A216-WCB
Special Coating
---
---
Electroless Nickel-Coated
Electroless Nickel-Coated
Table 2: Internal Trim Material Specifications
Item Par t
No. Description
for .375" & .75" valves
Trim: -D
Trim: -N
For 1" & 1.25" valves
Trim: -B
Trim: -D
For 1.5" & 2" valves
Trim: -N
Trim: -B
Trim: -D
Hard-Faced
Steel
Hard-Faced
Steel
Cast Iron with
#420 Stainless
Steel Seat Ring
Hard-Faced
Steel
Zinc-Plated
Steel
Zinc-Plated
Steel
#416 Stainless
Steel
#416 Stainless
Steel
2
Hex Nut or Renewable
Seat
Cast Iron with
Hard-Faced Steel Hard-Faced Steel #420 Stainless
Steel Seat Ring
3
Stem Bushing
Zinc-Plated Steel Zinc-Plated Steel
4
Stem
#416 Stainless
Steel
#416 Stainless
Steel
#416 Stainless
Steel
#416 Stainless #416 Stainless
Steel
Steel
#416 Stainless
Steel
#416 Stainless
Steel
5
Stem Spring
#302 Stainless
Steel
#302 Stainless
Steel
#302 Stainless
Steel
#302 Stainless #302 Stainless
Steel
Steel
#302 Stainless
Steel
#302 Stainless
Steel
6
Disc Carrier
Steel
Steel w/Nedox
coating
Steel
Steel
Steel w/Nedox
coating
Steel
Steel
7
Disc
Nodular Iron
Hard-Faced
Steel
Hard-Faced
Steel
Nodular Iron
Hard-Faced
Steel
8
Stem O-Rings
Viton
Viton
9
Disc Spring
10 Inner Stem Thrust Ring
11 Back-up O-Rings
Hard-Faced Steel Hard-Faced Steel
Zinc-Plated
Steel
Hydrin
Hydrin
Viton
#302 Stainless
Steel
#302 Stainless
Steel
#302 Stainless
Steel
Teflon
Teflon
Teflon
#302 Stainless #302 Stainless
Steel
Steel
Teflon
Teflon
Viton
Viton
#302 Stainless
Steel
#302 Stainless
Steel
Grafoil
Teflon
Teflon
Teflon
Teflon
Teflon
Teflon
---
---
12 Body Gaskets
Soft Iron
Soft Iron
Soft Iron
Soft Iron
Soft Iron
Soft Iron
Soft Iron
13 Stem Bushing Gasket
Soft Iron
Soft Iron
Soft Iron
Soft Iron
Soft Iron
Soft Iron
Soft Iron
14 Body O-Ring
Viton
Viton
Viton
Viton
Viton
---
---
15 Stem Packing Ring
Grafoil
Grafoil
---
---
---
---
---
---
---
---
---
---
---
Steel (same as
body material)
Steel (same as
body material)
16 Packing Nut
17 Outlet Flange
1/99
Zinc-Plated Steel Zinc-Plated Steel
---
---
---
---
Page 6118
Maxon Valv
es
alves
Swinging Gate Body/T
Body/Trr im Specifications
Typical construction of
.375" through .75" screwed body valves
Typical construction of
1" through 2" screwed body valves
Typical construction of
1.5" through 2" flanged body valves
Maxon Valv
es
alves
Page 6119
Component Identification
General Maintenance and Spare Parts
To determine suggested spare parts, identify
series designation and serial number from the valve’s
nameplate. Refer to the illustration and legend below
to identify suggested spare parts.
All safety devices should be tested at least
monthly* and more often if deemed advisable.
Periodic testing for tightness of manual or motorized shut-off valve closure is equally essential.
*per NFPA 86-Appendix B-4 (1995)
To order, specify:
1. Quantity
2. Assembly part number (if available)
3. Description
4. Electrical specification
5. Full nameplate information (from existing valve)
These Maxon valves are designed for long troublefree service. Only items shown as suggested spare
parts are considered field replaceable.
WARNING: Do not attempt field repair of valve
body, top assembly or motor drive unit. Any
alterations void all warranties.
Manual Reset
Nameplate
(typical)
Automatic Reset
Note: Drawings are illustrative only. Actual valves may vary slightly.
(shown for listed
valves; others
similar)
Nameplate
designation does
not reflect external
accessory items or
motor limit switch
1
1
2
3
2
Series 808
Normally closed valve designation
3
Series 5000
3" 5000-S CP D
VCS Used *
DC Solenoid (if used)
CP Body (if used)
Steel Body (if used)
Valve Series
Valve Size (NPT)
TO CLUTCH
1
2
12
11
10
9
8
7
6
5
4
3
2
1
4
*Signal Switch legend:
#1 BLACK TO
COM
TERMINAL #1
NC
NO
0 No Switch
2 VCS-2 Switch
1 VCS-1 Switch
2H VCS-2 (Herm. Sealed)
1H VCS-1 (Herm. Sealed)
BLACK TO MOTOR
#3 BLACK TO
TERMINAL #3
2
Series 808-CP
Normally open valve designation
Series 7000
Legend:
1 – Nameplate
2 – Solenoid
3 – VOS motor limit/signal
switch for normally closed
valve; VCS for normally
open valve
4 – Printed Circuit Board
(PCB)
2
4
SHUT
3" STO-AS CP D
2
VOS Used *
DC Solenoid (if used)
CP Body (if applicable)
Steel Body (if used)
Valve Series
Valve Size (NPT)
*Signal Switch legend:
Series 8700
1/08
0 No Switch
2 VOS-2 Switch
1 VOS-1 Switch
2H VOS-2 (Herm. Sealed)
1H VOS-1 (Herm. Sealed)
Page 6120
Maxon Valv
es
alves
Electrical Data
for normally closed valves
General
Diagrams show valve in its normally closed (at rest)
position. The indicated internal wiring is present only
when the appropriate auxiliary switches are specified.
Automatic reset valves always include a VOS-1 SPDT
valve open motor limit switch.
Good practice normally dictates that auxiliary
switches in valves used for safety shut-off functions
should be used for signal duty only
only, not to operate
additional safety devices.
All Maxon shut-off valves are electrically actuated
from a power source, normally through the flame
safeguard and/or safety control circuits.
Standard valve assemblies include an internal
holding solenoid or printed circuit board for 115 volt 60
hertz AC power. (Other electrical current options are
available upon request.)
Series 808, 730, 760, 5000, 4730, and 4760 valves
have the internal solenoid. Series 8700 and 7000
valves incorporate the printed circuit board.
The solenoid (or the printed circuit board) is energized whenever the valve is powered. The motor
operator on automatic reset versions is powered only
during the opening stroke.
Switch wiring diagrams (reproduced on the next
page) are part of each valve assembly, summarizing
electrical data and wiring for a valve equipped with
terminal block and a full complement of optional signal
switches.
Signal switch designations:
VCS (Valve Closed Switch) is actuated at the end
of the closing stroke. VCS-1 is SPDT; VCS-2 is
DPDT.
VOS (Valve Open Switch) is actuated at the end of
the opening stroke. VOS-1 is SPDT; VOS-2 is DPDT.
Switch amp ratings are shown on the schematic
wiring diagrams on page 6122. DO NOT EXCEED
rated amperage or total load shown.
Volt Ampere (VA) Ratings: Manual Reset
Valve
Size
AC Operation
Series
.75" – 1.5" 808, 818 (-S)
2" - 3"
808, 818 (-S)
1" - 1.25" 730, 760, 790 (-S)
1.5" - 2"
DC Operation
Opening
Holding
Opening
Holding
22
22
14
14
22
22
24
24
22
22
24
24
23300
22
22
24
24
1" - 1.25" 33790
22
22
24
24
2.5" - 4"
808-CP, 818 -CP (-S)
34
34
24
24
808, 818 (-S)
34
34
---
---
6"
Volt Ampere (VA) Ratings: Automatic Reset
Valve
Size
AC Operation (115 VAC, 60 Hz)
Series
DC Operation (24 VDC)
Opening
Holding
Opening
Holding
.75" – 1.5"
5000, 5100 (-S)
220 [1]
22
212
14
2" - 3"
5000, 5100 (-S)
220 [1]
22
222
24
1" – 1.25"
4730, 4760, 4790 (-S)
220 [1]
22
222
24
1.5" – 2"
25300
220 [1]
22
222
24
1" – 1.25"
33479
220 [1]
22
222
24
5000-CP, 5100-CP (-S)
232 [2]
34
222
24
376
8
428 [3]
8 [3]
143
5
---
---
2.5" – 4"
4" – 6"
7000, 7100 (-S)
.375" – .75" 8730, 8760, 8790 (-S)
[1] 220 VA shown is for 60 her tz; if 50 her tz power, VA rating is 342
[2] 232 VA shown is for 60 her tz; if 50 her tz power, VA rating is 354
[3] Based on 120 VDC
NOTE: The VA rating shown in the DC column is based on an AC motor, DC solenoid.
Maxon Valv
es
alves
Page 6121
Electrical Data
for normally closed valves
Manual Reset Series:
.75" – 3" Series 808, 818 (-S);
1" – 1.25" Series 730, 760, 790 (-S);
1" – 1.25" Series 33790 (-S);
2.5" – 4" Series 808-CP, 818-CP (-S);
6" Series 808, 818 (-S)
Automatic Reset Series:
.75" – 3" Series 5000, 5100 (-S);
1" – 1.25" Series 4730, 4760, 4790 (-S);
1" – 1.25" Series 33479;
2.5" – 4" Series 5000-CP, 5100-CP (-S)
4"– 6" Series 7000, 7100 (-S)
.375" through .75"
Series 8730, 8760,
and 8790 (-S)
1/08
Page 6122
Maxon Valv
es
alves
Electrical Data
for normally open valves
General
Signal switch designations:
All Maxon normally open vent valves are electrically actuated from a power source, normally through
the flame safeguard and/or safety control circuits.
Standard valve assemblies include an internal
holding solenoid for 115 volt 60 hertz AC power.
(Other electrical current options are available upon
request.)
The solenoid is energized whenever the valve is
powered. The motor operator on automatic reset
version is powered only during the closing stroke.
Switch wiring diagrams (reproduced below and on
next page) are part of each valve assembly, summarizing electrical data and wiring for a valve equipped
with terminal block and a full complement of optional
signal switches.
Diagrams show valve in its normally open (at rest)
position. The indicated internal wiring is present only
when the appropriate auxiliary switches are specified.
Automatic reset valves always include a VCS-1 SPDT
valve closed motor limit switch.
Good practice normally dictates that auxiliary
switches in valves used for safety shut-off functions
should be used for signal duty only
only, not to operate
additional safety devices.
VCS (Valve Closed Switch) is actuated at the end
of the closing stroke. VCS-1 is SPDT; VCS-2 is
DPDT.
VOS (Valve Open Switch) is actuated at the end of
opening stroke. VOS-1 is SPDT; VOS-2 is DPDT.
Switch amp ratings are shown on the schematic
wiring diagrams below and on the next page. DO
NOT EXCEED rated amperage or total load shown.
Volt Ampere (VA) Ratings
Valve
Size
AC Operation
Series
Closing
Holding
DC Operation
Closing
.75" – 1.5"
STO-M
22
22
14
14
2" - 3"
STO-M
22
22
24
24
24
2.5" – 4"
STO-M CP
34
34
24
.75" – 1.5"
STO-A
220 [1]
22
212
14
2" - 3"
STO-A
220 [1]
22
222
24
2.5" – 4"
STO-A CP
232 [2]
34
222
24
[1] 220 VA is for 60 her tz; if 50 her tz, then VA is 342
[2] 232 VA is for 60 her tz; if 50 her tz, then VA is 354
The VA rating shown in the DC column is based on an
AC motor, DC solenoid.
.75" – 2" Series STO-M and STO-A (-S)
2.5" – 4" Series STO-M-CP and STO-A-CP (-S)
P/N 26379M
SWITCH CONTACT POSITIONS
SHOWN WITH VALVE OPEN
VALVE WIRING DIAGRAM
MOTORIZED VALVE ONLY
VCS-1
VCS-2
VOS-1
VOS-2
SOLENOID
WARNING!
VALVE
MUST BE
WIRED AS
SHOWN
INTERNAL
WIRING
MTR
H(+)
N(-)
1
OPTIONAL
D.C. POWER
SUPPLY
ALL NI VALVES INCLUDE
HERMETICALLY SEALED
SWITCHES, SUITABLE FOR
HAZARDOUS LOCATIONS
CLASS I, DIV. 2, ABCD
CLASS II, DIV. 2, FG
CLASS III, DIV. 2
2
3
4
SPDT
5
6
7
8
9
10
SPDT
SPDT
11
12
SPDT
HERMETICALLY SEALED
HERMETICALLY SEALED
FIELD
WIRING
DPDT
DPDT
GENERAL PURPOSE
GENERAL PURPOSE
L1-H L2-N
AC-POWER
SEE NAME PLATE FOR VOLTAGE AND HZ
SWITCH RATINGS
VALVE
Total connected load not to exceed 1700 VA
MODE
GENERAL PURPOSE
HAZARDOUS LOCATION
DPDT
SPDT
SPDT
FULLY OPEN
125 VAC - 10 AMP
125 VAC - 15 AMP
28 VDC - 5 AMP
250 VAC - 10 AMP
INTERMEDIATE
250 VAC - 15 AMP
125 VAC - 1 AMP
125 VDC - 0.3 AMP
125 VDC - 0.5 AMP
FULLY SHUT
250 VDC - 0.25 AMP
250 VDC - 0.15 AMP
Holding
VCS-1
1-3
1-3
VCS-2
4-5
4-6
VOS-1
7-8
7-9
7-8
VOS-2
7-9 10-11 10-12
Maxon Valv
es
alves
Page 6123
Dimensions
(in Inches)
808, 5000, STO-A, STO-M
.75" through 1.5" valves with rising stem bodies
Available
Top Assembly
Positions
7.34
1.87
5.5
B
3.49
2.0
K
(2) 3/4" NPT
Conduit
Connection
D
A G
Pipe Size
2.3
“R”
“L”
“AW”
“TO”
(2) 1/4" NPTF
Test Connection
H
C
J
5000 & ST
O-A
STO-A
11.5
7.13
5.44
R
3.5
4.5
2.0
1.87
B
9.17
(2) 3/4" NPT
Conduit Connection
D
A G
Pipe Size
Pipe
Size
.75"
1"
1.25"
1.5"
1/04
(2) 1/4" NPTF
Test Connection
H
C
J
2.33
NOTE: 2.75" needed
for terminal block
cover removal.
808 & ST
O-M
STO-M
Valve
Series
A
B
C
D
G
H
J
K
808 & STO-M
5000 & STO-A
808 (-S) & STO-M (-S)
11.58
2.00
12.25
3.81
1.90
.78
1.94
.81
8.11
5000 (-S) & STO-A (-S)
808
5000
808 (-S) & STO-M (-S)
5000 (-S) & STO-A (-S)
R
--11.58
---
2.44
12.81
.22
4.00
2.69
13.31
2.00
1.56
8.67
1.68
9.14
2.12
.38
12.14
--12.61
---
Page 6124
Maxon Valv
es
alves
Dimensions
(in Inches)
808, 5000, STO-A, STO-M
2" through 3" valves with rising stem bodies
Available
Top Assembly
Positions
5000 & ST
O-A
STO-A
2.38
2.9
7.61
7.51
1.97
3.5
B
K
(2) 3/4" NPT
Conduit
Connection
D
G
A
Pipe Size
(2) 1/4" NPT
Test Connection
H
C
J
“R”
“L”
“AW”
“TO”
S
J
L
G
M
N
P
A
H
T
Equally spaced
13.12
8.55
7.61
2.73
2.38
1.97
5.63
R B
K
D
G
A
NOTE: 2.75" needed
for terminal block
cover removal.
Pipe Size
H
C
J
808 & ST
O-M
STO-M
Pipe
Size
2"
2" F
2.5"
Valve
Series
A
B
808 (-S) & STO-M (-S)
5000 (-S) & STO-A (-S)
808 & STO-M
5000
2.5" F
808 & 5000
3"
808 & 5000
D
G
H
J
K
4.38 2.19
3.25 14.75
5000 & STO-A
808
C
3.50
M
N
P
---
---
---
---
.44 2.25 1.88 10.6
---
---
5.0
2.5
14.62
---
L
---
---
2.94 14.86 5.19 2.59
.63
S
T
---
---
14.38
3.01 2.38 .75
2.12 2.25
R
---
---
3.50 7.0
4
---
---
3.5 2.75 .75
4
14.25
---
---
10.46
2.5
2.0
2.12 2.56 10.71 ---
---
---
---
---
3.75 7.5
---
---
Maxon Valv
es
alves
Page 6125
Dimensions
(in Inches)
808-CP, 5000-CP, STO-MCP, STO-ACP
2.5" CP through 4" CP and 6" valves with rising stem bodies
Series 808 (-CP) & STO-M (-CP)
15.12
10.94
8.87
2.83
5.7
4.2
R
Available
Top Assembly
Positions
B
A
A
6.09
A
D
7.25
G
Pipe Size
A
3.0
0.88
11.68
(2) 3/4" NPT
Conduit
Connection
(2) 1/4" NPTF
Test Connection
H
C
J
View A-A
S
“R”
“L”
L
Pipe Size
N (dia.)
P (no. of holes)
M
A
8.87
(2) 1/4" NPTF
Test Connection
H
T
Equally spaced
4.2
2.83
7.51
“AW”
B
A
6.07
A
7.25
G
(2) 3/4" NPT
Conduit
Connection
Pipe
Size
2.5" CP
2.5" F
CP
(2) 1/4" NPTF
Test Connection
A
3.0
0.88
“TO”
D
11.68
NOTE: 2.75" needed
for terminal block
cover removal.
H
C
View A-A
J
Series 5000 (-CP) & STO-A (-CP)
Valve
Series
808 (-SCP)
5000 (-SCP), STO-A (-SCP)
808 (-SCP)
5000 (-SCP), STO-A (-SCP)
A
B
4.31
C
D
G
5.0
2.5
.50
14.56
H
J
L
M
N
P
2.25
---
---
---
---
2.2
3.5
2.75
.75
4
2.56
---
---
---
---
2.12
4.5
---
---
5.12
5.5 2.75
---
808 (-SCP)
3"
CP
5000-CP, STO-ACP
808 (-SCP)
5000 (-SCP), STO-A (-SCP)
808 (-SCP)
4" F
CP
5000 (-SCP), STO-A (-SCP)
6"
808
10/02
14.56
--14.56
---
S
T
---
---
3.75
7.5
---
---
4.0
8.0
4.5
9.0
5.25
10.5
17.97
.62
2.12
5000 (-SCP), STO-A (-SCP)
3" F
CP
R
--17.97
5.22
15.29
2.24
---
---
20.75
---
---
3.75
3.0
---
5.55
7.5
2.6
---
4
.75
2.25
2.56
4.5
3.75
3.38
---
5.5
4.75
8
.88
8
17.97
--17.97
--23.43
Page 6126
Maxon Valv
es
alves
Dimensions
(in Inches)
4" & 6" 7000 Valves
8.63
E
3.87
(2) 3/4" NPT
Conduit
Connection
4.56
B
G
P
Pipe Size
R
A
S (dia.)
8 holes
equally spaced
(2) 1/4" NPTF
Test Connection
3.25
H
Available Top Assembly Positions
“R”
Valve Size
Valve Series
“L”
“AW”
“TO”
A
B
E
G
H
P
R
S
4"
7000 (-S) & 7100 (-S)
7.31
23.88
4.19
4.5
9
4.5
3.75
0.75
6"
7000 (-S) & 7100 (-S)
8.38
25
5.81
5.25
10.5
5.5
4.75
0.88
Maxon Valv
es
alves
Page 6127
Dimensions
(in Inches)
8700, 23300, 25300
.375" through 2" valves with swinging gate bodies
Series 8730, 8760, 8790 & 8790-S (.375", .5" & .75")
6.22
2.72
6.42
3.93
11.06
Note: Series 8700 valves are
available in top assembly positions
"R" and "TO" only.
3/4" Conduit
Connection
Pipe Size
3.18
1.19
2.30 (for .375")
1.69 (for .5" & .75")
2.93
Series 23300 & 25300 (1.5" & 2")
Available Top Assembly Positions
for Series 23300 & 25300
13.14
8.79
2.9
D
C
E
N
F
K
P
“L”
“R”
“TO”
“AW”
Pipe Size
7.59
C
A
S (dia. of holes)
T (no. of holes)
R
J
G
H
2.9
D
E
8.75
K
P
NOTE: 2.75" needed
for terminal block
cover removal.
Pipe Size
R
J
Valve Size
1.5"
2"
10/02
A
S (dia. of holes)
T (no. of holes)
Valve Series
G
H
A
23300 & 25300 3.06
23300 & 25300
3.25
C
D
7.62 2.38
E
F
3.5
5.62
G
H
2.44
11.44
2.69
11.94
J
2.72
K
N
P
R
S
T
18.00 18.00 3.06
2.25
0.88
4
18.37 18.37 3.25
2.5
0.75
8
Page 6128
Maxon Valv
es
alves
Dimensions
(in Inches)
4700, 700, 33479, 33790
1" & 1.25" valves with swinging gate bodies
1" & 1.25" Series 700, 4700
13.14
8.82
C
2.77
D
1" & 1.25" Series 33790, 33479
3/4"
Conduit
Conn.
5.7
E
16.08 16.28
Pipe Size
1.44
1.44
7.63
C
2.77
D
G
H
E
7.56
3/4" Conduit
Connection
16.28
B
Pipe Size
1.44
2.94
G
H
Available Top Assembly Positions
NOTE: 2.75" needed
for terminal block
cover removal.
"L"
Valve Size
Valve Series
730, 760, 790 & 790-S
1"
4730, 4760, 4790 & 4790-S
33790 & 33479
730, 760, 790 & 790-S
1.25"
4730, 4760, 4790 & 4790-S
33790 & 33479
"TO"
"R"
B
C
D
E
"AW"
G
13.53
--13.53
---
H
4.12
7.62
2.38
3.5
1.94
4.19
Maxon Valv
es
alves
Page 6129
Auxiliary Signal Switches
All Maxon valves may be equipped with internallymounted signal switch(es) to provide a “proof-ofopen” or “proof-of-closure” valve position indication.
Auxiliary signal switches indicate when valve is open
or closed and are normally connected electrically into
your control panel lights or warning device circuit(s).
For normally-closed valves:
VCS (Valve Closed Switch) is actuated when valve
is fully shut. It is the upper, inverted snap-switch
mounted on rear of switch bracket. VCS-1 is an SPDT
(single-pole, double-throw) switch. VCS-2 is a DPDT
(double-pole, double-throw) switch. All contacts are
available for external circuitry.
VOS (Valve Open Switch) is actuated when valve
reaches full-open. It is the lower snap-switch mounted
on front of switch bracket. VOS-1 is an SPDT switch.
On automatic reset valves, its normally closed contact
serves as a motor limit switch and is not available for
external circuitry. On manual reset valves, normally
closed contact is available for external circuitry, but is
not wired to optional terminal block. VOS-2 is DPDT,
used in lieu of VOS-1 for additional contacts.
VOS actuator
VOS
VCS
(VOS-2 shown)
(VCS-2 shown)
VOS wands
VCS wand
VOS actuator
VCS actuator
VCS actuator
Valve Open
Valve Shut
Photos above of normally-closed valve
(typical for Series 730, 760, 790, 808, 818, 5000, 5100, 4730, 4760, 4790)
1/99
Page 6130
Maxon Valv
es
alves
Auxiliary Signal Switches
For normally-open valves:
VOS (Valve Open Switch) is actuated when valve
is fully open. It is the upper, inverted snap-switch
mounted on rear of switch bracket. VOS-1 is an SPDT
(single-pole, double-throw) switch. VOS-2 is a DPDT
(double-pole, double-throw) switch. All contacts are
available for external circuitry.
VCS (Valve Closed Switch) is actuated when valve
reaches fully-closed. It is the lower snap-switch
mounted on front of switch bracket. VCS-1 is an
SPDT switch. On automatic reset valves, its normally
closed contact serves as a motor limit switch and is
not available for external circuitry. On manual reset
valves, normally closed contact is available for
external circuitry, but is not wired to optional terminal
block. VCS-2 is DPDT, used in lieu of VCS-1 for
additional contacts.
VCS actuator
VOS
(VOS-2 shown)
VCS
VOS wand
(VCS-2 shown)
VOS actuator
VCS wand
VCS actuator
Valve Shut
Valve Open
Photos above of normally-open valve
(typical for Series STO-MCP (-S), STO-ACP (-S)
All Maxon proof-of-open and
proof-of-closure signal
switches work in a similar
manner; but due to different
styles and types of top assembly housings, the switches
appear in slightly different
positions in the various types of
valves. Illustrated below are
representative top housings for
4" – 6" Series 7000 (Fig. 3) and
.375" – .75" Series 8700 (Fig.
4) valves. Switch locations are
noted on sketches.
Fig. 3
Fig. 4
Maxon Valv
e Accessor
ies
alve
Accessories
Page 6131
Tandem Arr
angements
Arrangements
(for simultaneous opening of main and blocking valves)
General
Wiring Schematic
Wherever insurance underwriters or other regulatory groups require the use of a double-valve or
"block-and-bleed" system, but manual operation is
preferred to the use of automatic reset valves, operation can be simplified by adding a tandem arrangement to a pair of Maxon manual reset shut-off valves.
A linkage overtravel spring in the tandem arrangement latches the blocking valve just before the main
valve is latched, assuring latching of both valves.
If it is necessary to locate a tandem valve above
arms reach, an overhead wheel and chain assembly
may be added which includes a loop of chain accessible to operating personnel.
Flame
Safeguard
Contact
Main Valve
(Normally Closed)
Blocking Valve
(Normally Closed)
VCS in
Main Valve
Vent Valve
(Normally Open)
VOS in
Main Valve
VOS in
Blocking Valve
For Illustration Only
(not a wiring diagram)
To order
Valves are to be specified in the usual manner and
must be in top assembly position TO or AW.
VOS and VCS switches must be included on the
main valve and a VOS switch on the blocking valve to
permit electrical connection as shown in the wiring
schematic illustrated at right.
If overhead wheel and chain assembly is also
required, specify loop length to reach appropriate
operating position. Extra chain (in one foot increments) may be specified.
Center line distance between valves must be within
the ranges indicated in Table 1 and shown in sketch
below and must be specified at the time of order.
Main Fuel
Panel Light
Main valve and blocking valve wired in parallel.
VCS Switch on main valve powers vent valve.
VOS Switches on main and blocking valves
wired in series to signal light.
Table 1: Allowable Valve Spacing for Tandem Arrgt.
Tandem Arrangement with
Overhead Wheel & Chain
Valve Size
Minimum C-C
Maximum C-C
.75" – 1.5"
18"
24"
2" – 3"
20"
27 "
4" & 6"
27"
33 "
Tandem Arrangement
Blocking
Valve
Blocking
Valve
Tension
Spring
Tension
Spring
Flow
Piping by others
1/99
Specify
loop length
if overhead
wheel &
chain option
Flow
Piping by others
See Table 1
above
Page 6132
Maxon Valv
es
alves
Ov
erhead Wheel & Chain Assemb
ly
Overhead
Assembly
Overhead wheel and chain assembly allows
operation of a manual reset valve in an otherwise
inaccessible overhead location. A wheel is mounted
onto the handle of the valve. The attached chain is
weighted on one end and has a paddle handgrip on
the other.
Once the valve is electrically energized, pulling
down on the paddle will open normally closed versions or close normally open versions.
Maxon valve's free-handle design permits valve to
trip to its rest position on any power interruption.
Wheel and chain assembly includes a length of
chain to position the paddle handgrip slightly below
pipe centerline. A standard length of 7 feet of chain is
included with CP and larger valve sizes and 5 feet is
included with all other valves. Extra chain (in one foot
increments) may be specified to fit your specific
location.
Approximate envelope dimensions
(nominal, in inches)
Swinging gate valves
6.94
Rising stem valves
12.19
Maximum
12.19
Maximum
2.31 dia.
NOTE: Overhead wheel & chain can only be mounted
on swinging gate valves with the top assembly
position TO.
7.25
5.25
Maximum
4.06